1. Field of the Invention
This invention relates to a fixture for use during steps in the manufacturing process of a wing structure, and more particularly for a fixture to hold at least one wing sub-assembly structure for the Mark I Mod 2 (AIM-9) Sidewinder Missile.
2. Description of Related Art
The wing sub-assembly for the Sidewinder missile includes a forged aluminum frame and a honeycomb core over which an aluminum skin and metallic structural adhesive are bonded. The bonding process requires the application of heat and vacuum or positive pressure to the wing structure.
Production of the Sidewinder wing, or similar wing structures, sometimes commonly called the Chaparral wing, has been performed for approximately 15 years. Until the subject invention, manufacturers of the Sidewinder wing sub-assembly have been unable to manufacture such wings which meet all dimensional tolerances required by the U.S. government. In particular, the dimensions of the wing base had exceeded dimensional tolerances when measured at the final assembly. The United States government has been forced to accept the wings despite the variations from the specifications due to the inability of the manufacturers to meet the tolerances.
Through experimentation, the inventor has determined that the cause of the distortion in the final wing sub-assembly is caused by one or more of the following: internal stress in the wing forgings, stress caused by machining, distortion caused by clamping of irregular forged surfaces during machining, distortion caused by applying pressure, either through a vacuum, through the combination of vacuum and positive external pressure, or mechanical pressure, to the wing surfaces during the heat bonding process, and shrinkage from bonding at high temperature and cooling.
The subject invention provides a fixture to which the wing structures are attached during the wing bonding process and which reduces and compensates for the distortions described above to provide a wing sub-assembly conforming to the specifications of the U.S. government for the base characteristics of the wing sub-assembly.
Advantages of the invention are set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.